It varies. You can do carpet shampoo, floor work, taking care of trash, recycling, clean up spills of blood or chemicals, snow removal. It depends on the building. I work in some of the medical buildings where there are different labs and experiments. Other people who work in residence halls do not deal with these different conditions. Yeah, you bet it can be dangerous. Some of the areas where people work have nuclear materials. There is a nuclear reactor that people work in. The people who work in nuclear areas require special training about safety. Animal testing labs can be dangerous. In the labs with mice, you have to be aware of what you are dealing with.